linux-kernel - Re: [PATCH 2/2] dt-bindings: leds: Add TI TLC5928 LED

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Message-ID: <20250331144525.GA2729915-robh@kernel.org>
Date: Mon, 31 Mar 2025 09:45:25 -0500
From: Rob Herring <robh@...nel.org>
To: Corentin Guillevic <corentin.guillevic@...le.fr>
Cc: Pavel Machek <pavel@....cz>, Lee Jones <lee@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, linux-leds@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] dt-bindings: leds: Add TI TLC5928 LED

On Wed, Mar 26, 2025 at 04:35:33PM +0100, Corentin Guillevic wrote:
> Document Texas Instruments TLC5928 LED driver devicetree bindings.
> 
> Signed-off-by: Corentin Guillevic <corentin.guillevic@...le.fr>
> ---
>  .../bindings/leds/leds-tlc5928.yaml           | 212 ++++++++++++++++++
>  1 file changed, 212 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/leds-tlc5928.yaml
> 
> diff --git a/Documentation/devicetree/bindings/leds/leds-tlc5928.yaml b/Documentation/devicetree/bindings/leds/leds-tlc5928.yaml
> new file mode 100644
> index 000000000000..0d857c9b1feb
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-tlc5928.yaml
> @@ -0,0 +1,212 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/leds-tlc5928.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: LED driver for TLC5928 from Texas Instruments.
> +
> +maintainers:
> +  - Corentin Guillevic <corentin.guillevic@...le.fr>
> +
> +description: |
> +  The TLC5928 is a LED controller handling up to 16 LEDs. It can
> +  control LED on/off using a SPI-compatible interface, and has an
> +  on/off control data shift register (blank) and data latch.
> +
> +  This driver also supports the daisy-chaining of several TLC5928
> +  chips, as illustrated by the diagram below (with two controllers):
> +
> +  +--------------+           +--------------+
> +  |          SCLK|-----+---->|SCLK     BLANK|--
> +  |              |     |     |              |
> +  |  SPI     MOSI|-----|---->|MOSI  TLC5928 |
> +  | Master       |     |     |        (1)   |
> +  |          MISO|<--+ |  +--|MISO          |
> +  |              |   | |  |  |              |
> +  |      CS/LATCH|-+-|-|--|->|LATCH         |
> +  +--------------+ | | |  |  +--------------+
> +                   | | |  |  +--------------+
> +                   | | +--|->|SCLK     BLANK|--
> +                   | |    |  |              |
> +                   | |    +->|MOSI  TLC5928 |
> +                   | |       |        (2)   |
> +                   | +-------|MISO          |
> +                   |         |              |
> +                   +-------->|LATCH         |
> +                             +--------------+
> +
> +  For more product information please see the link below:
> +  https://www.ti.com/product/TLC5928/part-details/TLC5928PWPR
> +
> +properties:
> +  compatible:
> +    const: ti,tlc5928
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +  reg:
> +    maxItems: 1
> +    description:
> +      SPI slave address
> +
> +  enable-gpios:
> +    description: |

Don't need '|' if no formatting.

> +      Array of GPIO specifiers, referring to the GPIO pins to enable/disable
> +      each device (active high to disable). In the daisy chain case, each
> +      GPIO has to be in the same sequence than the devices.
> +
> +  latch-gpio:

latch-gpios

-gpio is deprecated.

> +    maxItems: 1
> +    description: Latch GPIO (SPI chip select)
> +
> +patternProperties:
> +  "^spi-chip@[0-9]$":
> +    type: object
> +    unevaluatedProperties: false
> +    description: Properties for a TLC5928 controller.

I don't think this level is needed. Just encode the chip instance into 
the LED address. Either 1 cell splitting the bits or 2 cells with chip 
instance in 1st cell and LED# in the 2nd cell.

> +
> +    properties:
> +      '#address-cells':
> +        const: 1
> +
> +      '#size-cells':
> +        const: 0
> +
> +    patternProperties:
> +
> +      "^led@[0-9a-f]+$":

Don't need the '+' as the max is 'f'. That will change with the above 
though. You'll want something like '^led@[0-9a-f]+,[0-9a-f]$' with the 
chip and led numbers split.

> +        type: object
> +        $ref: common.yaml#
> +        unevaluatedProperties: false
> +        description:
> +          Properties for a single LED.